It's not as ancestrally-Democratic as the Deep South (during the 20th century, Republicans won MD-01 as often as Democrats), but yes, there are a lot of Dixiecrats on the Eastern Shore. There's also a big regional divide between the Eastern Shore and the rest of Maryland, which Kratovil was able to exploit (Harris lives in Baltimore County).

It was kind of a fluke too. Wayne Gilchrest not only endorsed Kratovil over Harris, but actively campaigned for him and totally trashed Harris whenever he could. Combine that with Harris being seen as too conservative at the time (this was before the Tea Party dragged the political center further to the right, remember), plus DCCC attention there for once, and you had Kratovil's razor-thin margin of victory for a single term.